This is a proposal to establish a Virology Core Laboratory for the AIDS Clinical Trials Group (ACTG) at the Clinical Virology Laboratory (CVL) at the University of Cincinnati. CVL, fully certified by the Virology Reference Laboratory (VRL) of the ACTG, will continue to serve as the Virology Laboratory at the University of Cincinnati AIDS Clinical Trials Unit, including the Pediatric Subunit at the Children's Hospital Medical Center and the Cincinnati Veteran's Administration Medical Center subunit, forming all protocol mandated virology studies for these units. In addition, utilizing the CVL's resources as a large diagnostic laboratory, we will perform at least 500 HIV cultures and 2,600 P24 antigen determinations on an annual basis. The CVL is geographically located in an area that is underserved by the ACTU and does not have other ACTU viral laboratories with extensive experience with HIV virologic techniques and strong records of VRL certification.